CSV Data Quality Checker
Score a CSV file for missing values and duplicates.
Runs in your browser. Nothing is uploaded — your input is processed on this device and discarded when you close the tab.
CSV Data Quality Checker
How to use this tool
- Paste CSV data with a header row on top.
- Press Check to see row and column counts, missing values per column and duplicate rows.
- Use Load sample for a 4-line file with one missing value pattern and one duplicate row.
Worked example
The sample has the header a,b and three data rows: 1 and blank, 1 and blank again, and 2 and 3. The report says 3 data rows and 2 columns, column b is missing in 2 of 3 rows (67%), and there is 1 duplicate row, because the first two data rows are identical.
What this tool does not do / Limits
Quoted fields and commas inside quotes are handled, but this checker reads the data as plain text: it cannot tell whether a value is factually correct, only whether it is present, repeated or of a consistent type. Files over a few thousand rows may feel slow in older browsers.
Frequently asked questions
What counts as a duplicate row?
Two data rows with exactly the same values in every column, after the checker reads them. Trailing spaces are not trimmed here, so rows that differ only by a space are not counted as duplicates.
What does the type guess mean?
A best guess from the values themselves — integer, number, date or text — not a promise about the source system.
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